subchannel_list.h | Explore in Territory

//
// Copyright 2015 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

#ifndef GRPC_SRC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_SUBCHANNEL_LIST_H
#define GRPC_SRC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_SUBCHANNEL_LIST_H

#include <grpc/support/port_platform.h>

#include <inttypes.h>
#include <string.h>

#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "absl/status/status.h"
#include "absl/types/optional.h"

#include <grpc/impl/connectivity_state.h>
#include <grpc/support/log.h>

#include "src/core/lib/channel/channel_args.h"
#include "src/core/lib/gprpp/debug_location.h"
#include "src/core/lib/gprpp/dual_ref_counted.h"
#include "src/core/lib/gprpp/manual_constructor.h"
#include "src/core/lib/gprpp/ref_counted_ptr.h"
#include "src/core/lib/iomgr/iomgr_fwd.h"
#include "src/core/lib/load_balancing/lb_policy.h"
#include "src/core/lib/load_balancing/subchannel_interface.h"
#include "src/core/lib/resolver/server_address.h"
#include "src/core/lib/transport/connectivity_state.h"

// Code for maintaining a list of subchannels within an LB policy.
//
// To use this, callers must create their own subclasses, like so:
//

// class MySubchannelList;  // Forward declaration.

// class MySubchannelData
//   : public SubchannelData<MySubchannelList, MySubchannelData> {
// public:
// void ProcessConnectivityChangeLocked(
//     absl::optional<grpc_connectivity_state> old_state,
//     grpc_connectivity_state new_state) override {
//   // ...code to handle connectivity changes...
// }
// };

// class MySubchannelList
//   : public SubchannelList<MySubchannelList, MySubchannelData> {
// };

//
// All methods will be called from within the client_channel work serializer.

namespace grpc_core {

// Forward declaration.
template <typename SubchannelListType, typename SubchannelDataType>
class SubchannelList;

// Stores data for a particular subchannel in a subchannel list.
// Callers must create a subclass that implements the
// ProcessConnectivityChangeLocked() method.
template <typename SubchannelListType, typename SubchannelDataType>
class SubchannelData { … };

// A list of subchannels.
template <typename SubchannelListType, typename SubchannelDataType>
class SubchannelList : public DualRefCounted<SubchannelListType> { … };

//
// implementation -- no user-servicable parts below
//

//
// SubchannelData::Watcher
//

template <typename SubchannelListType, typename SubchannelDataType>
void SubchannelData<SubchannelListType, SubchannelDataType>::Watcher::
    OnConnectivityStateChange(grpc_connectivity_state new_state,
                              absl::Status status) { … }

//
// SubchannelData
//

template <typename SubchannelListType, typename SubchannelDataType>
SubchannelData<SubchannelListType, SubchannelDataType>::SubchannelData(
    SubchannelList<SubchannelListType, SubchannelDataType>* subchannel_list,
    const ServerAddress& /*address*/,
    RefCountedPtr<SubchannelInterface> subchannel)
    : … { … }

template <typename SubchannelListType, typename SubchannelDataType>
SubchannelData<SubchannelListType, SubchannelDataType>::~SubchannelData() { … }

template <typename SubchannelListType, typename SubchannelDataType>
void SubchannelData<SubchannelListType, SubchannelDataType>::
    UnrefSubchannelLocked(const char* reason) { … }

template <typename SubchannelListType, typename SubchannelDataType>
void SubchannelData<SubchannelListType,
                    SubchannelDataType>::ResetBackoffLocked() { … }

template <typename SubchannelListType, typename SubchannelDataType>
void SubchannelData<SubchannelListType,
                    SubchannelDataType>::StartConnectivityWatchLocked() { … }

template <typename SubchannelListType, typename SubchannelDataType>
void SubchannelData<SubchannelListType, SubchannelDataType>::
    CancelConnectivityWatchLocked(const char* reason) { … }

template <typename SubchannelListType, typename SubchannelDataType>
void SubchannelData<SubchannelListType, SubchannelDataType>::ShutdownLocked() { … }

//
// SubchannelList
//

template <typename SubchannelListType, typename SubchannelDataType>
SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList(
    LoadBalancingPolicy* policy, const char* tracer,
    ServerAddressList addresses,
    LoadBalancingPolicy::ChannelControlHelper* helper, const ChannelArgs& args)
    : … { … }

template <typename SubchannelListType, typename SubchannelDataType>
SubchannelList<SubchannelListType, SubchannelDataType>::~SubchannelList() { … }

template <typename SubchannelListType, typename SubchannelDataType>
void SubchannelList<SubchannelListType,
                    SubchannelDataType>::StartWatchingLocked() { … }

template <typename SubchannelListType, typename SubchannelDataType>
void SubchannelList<SubchannelListType, SubchannelDataType>::Orphan() { … }

template <typename SubchannelListType, typename SubchannelDataType>
void SubchannelList<SubchannelListType,
                    SubchannelDataType>::ResetBackoffLocked() { … }

template <typename SubchannelListType, typename SubchannelDataType>
bool SubchannelList<SubchannelListType,
                    SubchannelDataType>::AllSubchannelsSeenInitialState() { … }

}  // namespace grpc_core

#endif  // GRPC_SRC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_SUBCHANNEL_LIST_H
chromium/third_party/grpc/src/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h
